#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>

int main()
{
    int a = 0;
    int b = 0;
    int c = 0;
    int d = 0;
    scanf("%d%d%d%d", &a, &b, &c, &d);
    float sum = a * 0.2 + b * 0.1 + c * 0.2 + d * 0.5;
    printf("%.1f\n", sum);
    return 0;
}